function [z,mu,sigma] = zscore(x,flag,dim)
%ZSCORE Standardized z score for tall arrays
% Z = ZSCORE(X)
% [Z,MU,SIGMA] = ZSCORE(X)
% [...] = ZSCORE(X,1)
% [...] = ZSCORE(X,FLAG,DIM)
%
% See also ZSCORE, MEAN, STD.
% Copyright 2015 The MathWorks, Inc.
if nargin < 2
flag = 0;
end
if nargin < 3
% We can't determine dim for tall arrays as the size might not be
% known. If not supplied, use the dimensionless versions.
validateFlag(flag)
mu = mean(x);
sigma = std(x,flag);
else
% User supplied dim
validateFlag(flag)
mu = mean(x,dim);
sigma = std(x,flag,dim);
end
% Now standardize X to give Z, taking care when sigma is zero
sigma0 = sigma;
subs = struct('type','()','subs',{{sigma0==0}});
sigma0 = subsasgn(sigma0, subs, 1);
z = (x - mu) ./ sigma0;
function validateFlag(flag)
validateattributes(flag,{'numeric'}, {'integer','scalar','binary'}, 2);
